Radiation Interactions with Matter

Question 1

List Characteristics of Alpha Radiation

Answer 1

Emitted from nucleus
Large 4 AMU
+2 charge
Mono-energic (range 3.5 - 10 MeV
Least penetrating ionizing radiation
Air Range- Several Centimeters
Tissue Range- micrometers
High internal Hazard

Question 2

Alpha Radiation interaction with Matter

Answer 2

Due size and =2 charge, interact readily with orbital electrons through both direct collisions and electrical field interaction through ionization and excitation. Expel energy quickly follow a short linear path.

Question 3

List characteristics of Beta Radiation

Answer 3

Emitted from Nucleus
Essentially energetic electron
1/1836 size AMU
mostly internal hazard
either negative (electron) or positive (positron)
spectrum of energies
more penetrating than Alpha

Question 4

Beta Radiation interaction with matter

Answer 4

Lose energy in a diffuse manner over a long winding path. Through direct collisions and electric field interactions such as ionization, excitation, and Bremsstrahlung.

Question 5

Origins of gamma radiation

Answer 5

Gamma Rays are emitted from nucleus when a proton
drops from a higher energy to a lower energy state. the difference is released as a gamma ray

Question 6

Properties of a Photon

Answer 6

have energy
no mass
no charge
have momentum
travel at speed pf light (3x10^8) m/s

Question 7

State the origin of X-ray

Answer 7

Emitted from the electron field or electron interactions
Characteristic X-ray (from electron field)
Bremsstrahlung X-ray- from free electron slowing

Question 8

Characteristic X-ray

Answer 8

Produce when electron from higher orbital shell drops down to fill a vacancy in lower orbital
difference in energy released as X-ray
Difference in binding energies is unique for different atoms

Question 9

Bremsstrahlung X-ray

Answer 9

High speed charged particles undergo radial acceleration due to change in direction of travel. releases X-ray

Question 10

Photon interaction with matter
3 types

Answer 10

Photoelectric effect
Compton Scattering
Pair Production

Question 11

Photoelectric Effect

Answer 11

Photon interacts with an orbiting electron, freeing it with kinetic energy

Question 12

Compton Scattering

Answer 12

Photon interacts with an orbiting electron, freeing it with kinetic energy. New. lower energy photon is emitted

Question 13

Pair Production

Answer 13

A photon of sufficient energy >1.022 MeV. in the presence of a highly charged nucleus. splits into an electron-positron pair

Question 14

Characteristic of Neutron Radiation

Answer 14

Emitted from the nucleus of an atom as a result of nuclear fission
spectrum of energies
Born fast >1MeV
Mass of 1 AMU

Question 15

Fast Neutron Radiation interaction with matter

Answer 15

Indirect ionizing radiation
Elastic scattering
Inelastic scattering

Question 16

Elastic Scattering

Answer 16

Energy remains kinetic energy of motion. Max energy when both objects are of same size. To stop a fast neutron, allow to collide with target atoms having a nuclear mass equal to the mass of a neutron. Best material rich in Hydrogen. Water. wax. concrete, and various plastics. Neutrons lose half of energy per interaction

Question 17

Inelastic scattering

Answer 17

Occurs when collision energy is used to raise the target nucleus into a higher nuclear level. When nucleus de-excites with an emission of a gamma ray.

Question 18

Thermal Neutron

Answer 18

Fast neutron eventually loses most of its kinetic energy and become a thermal neutron

Question 19

Thermal neutron interaction with matter

Answer 19

Radioactive Capture
Charged particle emission
Fission

Question 20

Relative capture

Answer 20

Neutron is captured by target nucleus and a gamma ray is emitted

Question 21

Charged particle emission

Answer 21

neutron is capture by target nucleus, the nucleus emits a charged particle

Question 22

Fission

Answer 22

Neutron is absorbed by nucleus causing it to split into two fission fragments releasing neutrons and gammas